public static void Main()
new { line = 1, ship="jonata", altro="baba"},
new { line = 1, ship="glauco", altro="baba"},
new { line = 2, ship="jonata", altro="baba"},
new { line = 2, ship="glauco", altro="baba"},
var aggregate = data.GroupBy(d => new {d.line, d.altro})
ship = string.Join(", ", g.Select(g2 => g2.ship))})
var json = JsonConvert.SerializeObject(aggregate);